The present invention relates to a centrifugal apparatus for projecting shots for a shot blast machine. Particularly, it relates to a mechanism to prevent a cover for an impeller from being abraded.
Conventionally, liners are put on the inner side of a cover for an impellers so that they surround the impeller of a centrifugal apparatus for projecting shots for a shot blast machine to prevent the cover from being abraded. Also, the liners are divided into pieces and used for front and rear sides, right and left sides, and an upper side. These sides are named based on the direction that the impeller rotates. The pieces are also divided into small pieces. Thus there is a problem in that there are too many pieces. Japanese Utility Model No. 2506549 discloses an improvement of the liners that are located at the front and rear sides. The liners are formed as U-shaped rain gutters as viewed from their cross-sections, so that the number of pieces may be decreased.
When any piece of the liners is abraded, a new one replaces it. The pieces of liners are engaged by screws to the cover for an impeller. When they are replaced, those screws must be unscrewed to remove the pieces from the cover. Then, new ones replace those pieces. These replacements are troublesome.
Because the pieces of the liners are screwed to the cover, the pieces tend not to closely contact the cover. Thus, those connections are easily abraded by shots. Thus, projecting members (shots) are projected out of the connections. Thus, the cover is also abraded.
This invention has been conceived to overcome the problems referred to above. The object of this invention is to provide a centrifugal apparatus for projecting shots wherein liners that have been abraded can be easily replaced by new ones, and wherein shots are prevented from being projected through the connection between the pieces and the cover, so that the cover can be definitely prevented from being abraded.
Thus, the object is achieved by the centrifugal apparatus for projecting shots of this invention. The apparatus comprises an impeller, a cover for the impeller surrounding it, and a liner that is located within the cover. The cover is comprised of first and second-side cover components located at right and left sides, front and rear cover components, and a ceiling cover component that can be opened and closed. The liner can be screwed to the cover, so that it can be disengaged from it. The liner is comprised of first- and second-side liner components each having an opening through which the rotating shaft of the impeller can pass, front- and rear-side liner components that are U-shaped and that are pressed against the ends of the first- and second-side liner components and fixed on them, and liner components that are pressed against the upper ends of the first- and second-side liner components and the front- and rear-side liner components and fixed on them.
Another concept of the centrifugal apparatus for projecting shots of this invention includes an impeller in which a hub, impeller-side plates, impeller blades, and a distributor are rotatably located on a rotating shaft, an impeller cover surrounding the impeller, and a liner. The impeller cover is comprised of first and second cover components located at right and left sides, front and rear cover components, and a ceiling cover component that can be opened and closed. The liner components can be screwed to the impeller cover, so that it can be disengaged from it.
The liner components are comprised of first- and second-side liner components having openings through which the rotating shaft of the impeller can pass, front and rear side liner components that are U-shaped and that are pressed against the ends of the first and second-side liner components and fixed on them, a frame-liner component that is engaged with the upper ends of the first- and second-side liner components and the front- and rear-side liner components, and a ceiling-side liner component that can be engaged with and disengaged from the frame-liner component. A labyrinthine structure is located at the connecting surfaces between the ceiling-side liner component and the first- and second-side liner components. The labyrinthine structure has four portions bent along the direction of the projection of the projecting members. The ceiling-side liner can be pressed against the impeller cover by a fixing member located on the impeller cover, and fixed on it.
A further concept of the centrifugal apparatus for projecting shots of this invention includes a protecting member for an impeller cover. The protecting member includes the impeller cover surrounding the front, rear, left, right, and ceiling sides of an impeller, first- and second-side liner components to protect the left and right sides of the impeller cover, front- and rear-side liner components to protect the front and rear sides of the impeller cover, a ceiling-side liner component to protect the ceiling side of the impeller cover, and a frame-liner component. The impeller cover comprises first- and second-side cover components having openings at the left and right sides, plate-like front and rear-side cover components at the front and rear sides, and a ceiling-side cover component that can be opened and closed at the upper side. The impeller cover is generally formed as a box shaped as a trapezoid. The first- and second-side liner components are generally shaped like trapezoids and have openings at the center through which the first- and second-side plates pass. The first- and second-side liner components are fixed on the impeller cover by screws. The front and rear-side liner components are formed as rain gutters that are U-shaped and inclined. The front- and rear-side liner components are pressed against and fixed on the right- and left ends of the first- and second-side liner components by bolts that are passed through the front and rear plates of the impeller cover. A labyrinthine structure is located at the connecting surfaces between the ceiling-side liner component and the first and second-side liner components. The labyrinthine structure comprises four portions bent in the direction of the projection of shots. The frame-liner component is shaped as a loop that comprises a vertical plate to define an opening so that the upper ends of the liner components that are engaged, pressed, and fixed within the impeller cover may pass through the opening. The frame-liner component is engaged with these upper ends. The ceiling-side liner component has a looped-projection formed along its periphery on its lower surface. The looped-projection is inserted into a U-shaped groove formed by the upper ends of the side-liner components and the vertical plates of the frame-liner component. The ceiling-side liner component is pressed down by a fixing member that is located on the impeller cover and fixed on the frame-liner component.